Facile chemical fabrication of Ni doped CoAl2O4 nano-spinel photocatalysts: Physico-chemical properties and photodegradation of toxic malachite green dye under visible light

ABSTRACT

In this present study, we report the facile chemical fabrication of Ni-doped CoAl₂O₄ (NCA) (Co_1-xNi_xAl₂O_4-δ, where x = 0.0, 0.05, 0.10, 0.15 and 0.20) nano-spinel photocatalyst materials by a simple chemical precipitation route. The XRD data revealed the presence of cubic crystal structure for CoAl₂O₄ and Ni-doped CoAl₂O₄ samples. Presence of vibration modes of M − O, Al−O, and M − O− Al in the spinel lattice structure in the materials was found out by FTIR analysis. The particle size analysis and SEM confirmed the presence of nanosized grains in the samples. The occurrence of appropriate amount of Co, Al, O and Ni was detected by EDAX analysis. The optical characteristics of Co_1-xNi_xAl₂O_4-δ were studied using UV spectral studies. The band gap energy (E_g) of NCA was found to be in the range of 2.14 to 2.32 eV. The photocatalytic activity studies confirmed that the fabricated NCA nanoparticles have good photocatalytic behaviour in the degradation of malachite green (MG) dye solution under visible light irradiation. Further, the obtained results revealed that the doping of Ni has influenced the structural, spectral, morphology and the photocatalytic properties of the CoAl₂O₄ spinel materials to a greater extent. In addition, the factors affecting the photo-degradation of MG including composition of photocatalyst, photocatalyst loading, pH of the dye solution and the irradiation time were investigated and reported. The studies indicate that the 15% Ni-doped CoAl₂O₄ is a promising candidate material among all for the photocatalytic degradation of highly toxic dyes such as MG.

KEYWORDS:

• Chemical synthesis
• Ni-doped CoAl₂O₄ catalyst
• photodegradation
• malachite green

Acknowledgments

ASN thanks Karunya Institute of Technology and Sciences (KITS) for promoting nanomaterials chemistry based research activity in the Department of Applied Chemistry. MAK thanks KITS for providing necessary research facilities to carry out this research work.

Disclosure statement

No potential conflict of interest was reported by the author(s).